Recently, terahertz (THz) photonic crystal waveguides based on sapphire shaped crystals have been proposed. These waveguides combine unique properties of sapphire with advantages of the edge-defined film-fed growth (EFG) or Stepanov technique of shaped crystal growth and allow guiding THz waves in a wide spectral range with small dispersion and losses. The sapphire photonic crystal waveguides are capable for operation in aggressive environment, which makes possible to perform high-temperature and high-pressure THz measurements, as well as THz measurements of aggressive chemicals. In this paper, the technological aspects of sapphire THz photonic crystal waveguide manufacturing by the EFG/Stepanov technique (including, the problems of seeding and automated control of multichannel shaped crystal growth) have been described. Prospective applications of sapphire photonic crystal waveguides in various branches of THz science and technology have been discussed.
In this paper, an advantage of sapphire shaped crystal use for highly efficient terahertz (THz) waveguiding is discussed. The THz photonic crystal waveguide has been manufactured using the edge-defined film-fed growth (EFG) or Stepanov technique of shaped crystal growth. The effective mode index and extinction coefficient of the waveguide have been experimentally studied using the THz pulsed spectroscopy. The observed results have shown that the multichannel sapphire crystal allows guiding the THz waves with minimal dispersion in frequency range of 1:0 to 1:55 THz and minimal loss of 2 dB/m at 1:45 THz. The waveguides based on sapphire shaped crystals can be employed in wide range of THz technology applications, including non-destructive evaluation of materials, medical diagnostics, and sensing in aggressive environment.